The invention pertains to an indexable cutting insert which presents visually perceivable indicia thereon which enables the operator to index the cutting insert to a pre-determined position thereby optimizing the use of the cutting insert.
Indexable cutting inserts of a generally cylindrical or frustoconical shape, i.e., so-called round cutting inserts (see American National Standard ANSI B212.4--1986), have many uses in material removal operations (e.g., machining). Because the cutting insert is of a generally cylindrical or frustoconical shape, it is difficult for the operator to ascertain exactly how far to rotate the cutting insert to index the same so as to present a completely unused cutting edge and still optimize the overall useful life of the cutting insert.
It is undesirable for a cutting insert to present a cutting edge that has a used portion. In order to make certain that the cutting insert presents an unused cutting edge, the operator typically indexes a round cutting insert more than the optimum extent because the operator wants to make certain that the cutting insert presents an unused cutting edge. However, when the operator indexes the cutting insert in such a fashion so as to avoid presenting a used cutting edge, it is typical that a certain portion or portions of the cutting edge will remain unused. Subsequent to the complete indexing of the cutting insert, it is impossible to use these unused portions of the cutting edge.
In many cases, indexable round cutting inserts are expensive in that they have an expensive substrate or use a hard coating of expensive material such as, for example, cubic boron nitride, polycrystalline diamond, diamond sheet, and the like. Because of the expense of the cutting insert, it would be desirable to provide a way by which the operator can index the cutting insert to as many indexable positions as practically possible while always presenting an unused cutting edge.